Metal effect pigments comprising a mixed inorganic/organic layer, method for the production of such metal effect pigments, and use thereof

ABSTRACT

The invention relates to metallic effect pigments with coating, comprising a platelet-shaped substrate, where the coating comprises at least one hybrid inorganic/organic layer, the hybrid layer having at least partly an inorganic network that has one or more inorganic oxide components, and having at least one organic component, the organic component being at least partly an organic oligomer and/or polymer which is covalently bonded at least partly to the inorganic network via one or more organic network formers. The invention further relates to a method of producing these metallic effect pigments, and to their use.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of prior U.S. patent applicationSer. No. 12/063,019, filed May 23, 2008, by Stefan Trummer, FrankHenglein and Mariel Brauer entitled “METAL EFFECT PIGMENTS COMPRISING AMIXED INORGANIC/ORGANIC LAYER, METHOD FOR THE PRODUCTION OF SUCH METALEFFECT PIGMENTS, AND USE THEREOF,” which is a 35 U.S.C. § 371 NationalPhase conversion of International Application No. PCT/EP2006/007737,filed Aug. 4, 2006, which claims priority of German Patent ApplicationNo. 10 2005 037 611.8, filed Aug. 5, 2005. The PCT InternationalApplication was published in the German language. The contents of eachof the patent applications above-listed are incorporated in full hereinby reference.

BACKGROUND OF THE INVENTION

The invention relates to platelet-shaped metallic effect pigments with ahybrid inorganic/organic layer, and to a method of producing them. Theinvention further relates to the use of these metallic effect pigments.The optical effect of metallic effect pigments is based on theirplatelet-shaped (or lamellar) structure, which leads to an orientationsubstantially parallel to the substrate in an application medium. Theplatelet-shaped structure of the oriented metallic effect pigments inturn produces effect-imparting properties such as, for example, alight/dark flop and also a high gloss.

The specific optical effect is very importantly determined by thepigment size and pigment size distribution and also by the averagethickness of the metallic effect pigments. In terms of theirplatelet-shaped structure, metallic effect pigments are sensitive to theinfluence of mechanical forces, and particularly of shearing forces. Byexcessive shearing operations they may become disintegrated or deformed,thereby impairing the effect-imparting properties. The sensitivity ofthe metallic effect pigments is manifested, for example, in the factthat the metallic effect pigments are easily damaged or disintegrated onpumping through the circuit line systems of automobile finishingequipment. Additionally, in contrast to conventional color pigments,metallic effect pigments must be incorporated gently into wet coatingmaterials, in order to avoid damage to the metallic effect pigments.Furthermore, metallic effect pigments cannot be incorporated, likechromatic pigments, by extrusion and subsequent grinding in a pinneddisk mill, into the base varnish of a powder coating material. In thatcase they would generally be comminuted to such an extent that thecharacteristic optical effects would be lost almost completely.

A further critical point relates to the corrosion resistance of metalliceffect pigments. Mention may be made here, for example, of the gassingstability of aluminum pigments in alkaline aqueous varnishes. In thesemedia, unprotected aluminum pigments undergo corrosion, giving offhydrogen, a phenomenon also referred to as “gassing”. This unwantedevent is associated with a potential for explosion, and, furthermore,oxidation robs the aluminum pigments of their typical opticalproperties. Furthermore, the hydrogen produced adversely affects therheological properties of the coating material.

For a relatively long time, therefore, metallic effect pigments havebeen provided with purely inorganic or with purely organicthree-dimensionally crosslinked coatings. These coatings generally serveas a protection against corrosion with respect to aggressive media, butoften also have a mechanically stabilizing action. Moreover, metalpigments which are used in the powder coating material may be given asuitable electrostatic chargeability by means of dielectric coatings.

Metal pigments can be coated, for example, with silicon dioxide (U.S.Pat. No. 2,885,366 and U.S. Pat. No. 3,954,496) or with acrylatepolymers (DE 40 30 727). SiO₂-coated metal pigments are availablecommercially and are sold by Eckart GmbH & Co. KG under the names PCR,Hydrolan®, and also Resist and Dorolan®. Silicon dioxide coats endowaluminum pigments, for example, with excellent gassing stability inaqueous varnish systems. Moreover, the hardness of such a coatingstabilizes the ductile and shear-sensitive aluminum flakes against theinfluence of shearing forces of the kind which occur, for example, inthe circuit line systems in automobile finishing equipment (A. Kiehl andK. Greiwe, Progress in Organic Coatings 37 (1999) 179).

A similar effect also occurs in the case of aluminum oxide coatings (DE195 20 312, H. Birner and K. Greiwe, Coating 11 (1997) 432). Also knownare chromated aluminum pigments (EP 0 259 592), where an imperviousmixed layer of aluminum oxide and chromium oxide provides for gassingstability.

The advantageous properties achieved through purely inorganic or purelyorganic three-dimensionally crosslinked coatings on metallic effectpigments must be distinguished from different surface coverings on thepigments. The aim of such surface coverings is always to improve theperformance properties, which are influenced by the surface chemistry ofthe metallic effect pigments. Thus, for example, the wetting of themetal pigments is influenced directly by the surrounding varnish medium.Thus DE 198 20 112 A1 describes reactive organic orientation assistantswhich are able to attach chemically to a functional group on the surfaceof a metallic effect pigment and to attach to another functional groupon the varnish. The organic orientation assistants are applied as aseparate coat to metallic effect pigments which have been giveninorganic oxide coats or organic polymer coats. The orientationassistants alter the surface properties of the metallic effect pigmentand allow covalent attachment to the binder of the varnish, therebyimproving on the one hand the orientation of the pigments in the varnishand on the other hand the condensation resistance of the cured varnish.

DE 196 35 085 A1 discloses aluminum pigments coated with a passivatingprotective coat and produced by Physical Vapor Deposition (PVD). Aprotective layer of inorganic oxides and organic oligomers and/orpolymers bonded covalently to one another is not described.

DE 40 30 727 A1 contains resin-coated metal pigments which on theirsurface first have a covalently bonded siloxane layer to which athree-dimensionally crosslinked synthetic resin coating is bondedcovalently. A disadvantage of these pigments is that they are not verystable toward corrosion. Additionally, this siloxane layer does notproduce effective mechanical attachment of the synthetic resin coatingto the metal pigments.

EP 1 322 714 A2 discloses a pigment preparation containing metalpigments coated with a silicon-oxygen matrix. This refers to pure SiO₂coatings and also to coatings with an SiO₂ matrix into whichorganofunctional silanes have been incorporated.

WO 03/014228 A1 discloses metal pigments which have been coated with afirst coat of phosphates or borates and with a second coat of SiO₂.According to the teaching of that specification the SiO₂ layer may alsocomprise organofunctional silanes.

A disadvantage of metallic effect pigments with a purely inorganiccoating, or of inorganic coats into which organosilanes have beenincorporated, is that these coats are very brittle. It has emerged that,under severe mechanical stress, these coats may be damaged, leading to aloss of desired properties.

Thus, for example, the processing of silicate-coated metallic effectpigments in a mixer can lead to a loss of gassing stability on the partof the pigments. In such an operation the pigments as a powder arepasted with solvent in the mixer, for example. These pastes possessextremely high viscosities. As a result, the mechanical shearing energyof the mixer blades imposes strong shearing forces on the metalliceffect pigments. The brittle SiO₂ coats may be mechanically broken bythe shearing forces which act. Thus, in certain circumstances, injury tothe coating of only a tiny fraction of the platelets is enough to leadto a reaction with surrounding water molecules, which first entails anexplosion risk and second leads to a deterioration in the opticalproperties as a result of corrosion, such a deterioration beingunwanted. For the production of metallic effect pigments in consistentquality, however, processing in a mixer is an unavoidable productionstep.

Quality detractions of this kind are the case even when the substrateused is an iron oxide-coated aluminum pigment (“Paliocrom”). Thesepigments can be made very stable to gassing, by means of a further SiO₂coating. In this case there are two successive inorganic coats, but theyare both brittle.

The problem of brittleness cannot be solved simply by increasing thethickness of the SiO₂ coat, or by similar measures, without having toaccept significant deteriorations in other performance properties.Increasing the coat thickness impairs the pigment's opacity and leads toan increasing deterioration in the optical properties of the metalpigment. Nor does an additional organic functionalization of the surfaceproduce any change in the fundamental brittleness of the SiO₂ coat.

A disadvantage of the purely organic coating of metallic effect pigmentsis that they are not sufficiently stable to gassing.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide metallic effectpigments having improved mechanical properties. The metallic effectpigments, even after exposure to strong shearing forces, are to exhibitgood optical properties in the application medium and are also topossess a good gassing stability.

The object on which the invention is based is achieved by provision ofmetallic effect pigments with coating, comprising a platelet-shapedsubstrate, where the coating comprises at least one hybridinorganic/organic layer, the hybrid layer having at least partly aninorganic network that has one or more inorganic oxide components, andhaving at least one organic component, the organic component being atleast partly an organic oligomer and/or polymer which is covalentlybonded at least partly to the inorganic network via one or more organicnetwork formers.

Preferred developments are specified in dependent claims 2-21.

The object is further achieved by provision of a method of producingmetallic effect pigments with hybrid inorganic/organic layer, whichcomprises the following steps:

-   -   reacting at least one inorganic network former and at least one        organic network former and at least one reactive organic        component in a liquid phase to form a coating composition,    -   applying the coating composition to platelet-shaped metallic        substrates as a hybrid layer, the platelet-shaped metallic        substrates being added to the liquid phase before, during or        after the addition or reaction of the at least one inorganic        network former and of the at least one organic network former        and of the at least one reactive organic component, the hybrid        layer having at least partly an inorganic network that has one        or more inorganic oxide components, and having at least one        organic component, the organic component at least partly being        an organic oligomer and/or polymer which is covalently bonded at        least partly to the inorganic network.

The at least one inorganic network former, the at least one organicnetwork former, and the at least one reactive organic component can becombined with one another in any order. The reaction conditions,however, must be set such that a reaction can take place between thecomponents. Preferably the reaction is accomplished by hydrolysis and/orcondensation of the components with one another. The components aretherefore hydrolyzable and/or condensable. The coating composition whichforms in the course of the hydrolysis and/or condensation is thenapplied to the metal pigment surface, preferably by precipitation.

The metal pigments can be added to the liquid phase before, during orafter the addition or reaction of the at least one inorganic networkformer and of the at least one organic network former and of the atleast one reactive organic component. Accordingly the metal pigments canbe first introduced in a liquid phase and then the inorganic networkformer(s), the organic network former(s), and the reactive organiccomponent(s) added in any order. Alternatively the metal pigments can beadded to the coating composition during the reaction or after thereaction. Depending on the order of the addition and on the reactionconditions applied, a predominantly inorganic or predominantly organiclayer may be applied first to the metal pigment surface, before thehybrid inorganic/organic layer is applied. The inorganic/organic layermay of course also be applied directly to the uncoated or precoatedmetallopigment surface.

DESCRIPTION OF PREFERRED EMBODIMENTS

According to one preferred development the method of the inventioncomprises the following steps:

-   (a) providing a reaction mixture of platelet-shaped metallic    substrates in a liquid phase,-   (b1) adding at least one inorganic network former to the reaction    mixture from step (a),-   (c1) hydrolyzing and/or condensing the inorganic network former    added in step (b1),-   (d1) adding at least one reactive organic network former and at    least one reactive organic component before, during and/or after the    hydrolysis and/or condensation of step (c1), or-   (b2) adding at least one reactive organic network former and at    least one reactive organic component to the reaction mixture from    step (a),-   (c2) adding at least one hydrolyzable or condensable inorganic    network former to the reaction mixture from step (b2),-   (d2) hydrolyzing and/or condensing the inorganic network former    added in step (c2), and-   (e) reacting hydrolyzed and/or condensed inorganic network former    with the reactive organic network former and also with the reactive    organic component, with simultaneous and/or subsequent deposition of    a hybrid inorganic/organic layer,-   (f) optionally separating the platelet-shaped substrates coated in    step (e) from the reaction mixture.

By inorganic network former in the sense of the invention is meant thatthe inorganic network former is able to construct an inorganic network.An inorganic network former may be, for example, a hydrolyzable metalsalt or else a fully hydrolyzable organometallic compound.

By an organic network former in the sense of the invention is meant thatthe organic network former is able, in conjunction with a reactiveorganic component, to construct an organic or organometallic network. Anorganic network former is preferably an organometallic compound which isonly partly hydrolyzable and so is unable to construct an inorganicnetwork.

The object on which the invention is based is also achieved through theuse of the platelet-shaped metallic effect pigment of any one of claims1 to 21 in varnishes, automobile finishes, paints, printing inks, powdercoating materials, architectural paints, plastics, security printinginks, ceramics, glass or cosmetic preparations.

The object on which the invention is based is further achieved throughthe use of the platelet-shaped metallic effect pigment of any one ofclaims 1 to 21 as IR (infrared light)-reflecting pigments in masonrypaints and/or architectural paints.

It has become apparent, surprisingly, that mechanically stable metalliceffect pigments that are also stable to gassing can be obtained if themetallic effect pigments are enveloped with a hybrid layer of organicoligomers and/or polymers and also with an inorganic network ofinorganic oxides. The organic oligomers and/or polymers are at leastpartly covalently bonded to the inorganic network. The inorganic networkis preferably interpenetrated by the at least partly covalently bondedorganic oligomers and/or polymers. In the sense of the invention, then,layers of inorganic oxides and organic oligomers and/or polymers areformed that are not separated from one another. Preferably a layer isformed in which the inorganic network and the organic oligomers and/orpolymers are in mutual interpenetration.

Surprisingly the hybrid layers of the metallic effect pigments of theinvention have a mechanical hardness which is comparable with those ofpure inorganic oxide layers. In contradistinction to pure inorganicoxide layers, the hybrid inorganic/organic layers of the metallic effectpigments of the invention are substantially more elastic, i.e.,substantially less brittle. The metallic effect pigments of theinvention are therefore substantially easier to handle, beingsubstantially less sensitive to mechanical exposure, such as shearingforces, for example. The improved mechanical stability is surprisinglyachieved without any impairment in the gassing stability.

It has become apparent, for example, that, following application of ahybrid layer of SiO₂ and organic oligomer and/or polymer to metalliceffect pigments, pigments are obtained which are stable to gassing andwhich remain stable to gassing even after processing in a mixer. Theorganic oligomers and/or polymers in this case are at least partlycovalently linked to the SiO₂ layer. The organic component raises theelasticity of the coating without substantially adversely affecting themechanical hardness. The result is an abrasion stability on the part ofthe coating that is improved significantly in comparison to purelyinorganic layers.

Furthermore it has emerged, surprisingly, that the improvement inmechanical stability through a hybrid inorganic/organic layer isobtained even when one (or more) further, purely inorganic oxide layersare deposited on this hybrid layer.

A further surprise is that, in the case of a hybrid inorganic/organiclayer, it is possible in fact to achieve improved protection of metalliceffect pigments against corrosion, as compared with pure organic orinorganic layers.

Accordingly, through the incorporation of organic oligomers and/orpolymers into inorganic oxide layers, performance properties of metalliceffect pigments are improvable in a wide diversity of ways.

In accordance with the invention the at least partial covalent bondingof the inorganic oxide network to the organic oligomer and/or polymertakes place via at least one organic network former. Organic networkformers are reagents able to attach both to the inorganic network and tothe organic oligomer and/or polymer.

According to one preferred embodiment the at least partial covalentbonding of inorganic oxide component and organic oligomer and/or polymeris accomplished at least partly through one or more organic networkformers, the organic network former preferably having the generalformula (I)R¹ _(n)R² _(m)R³ _(o)SiX_((4-n-m-o))  (I)

-   where X is a hydrolyzable group after whose hydrolysis a covalent    bond of organic network former to the inorganic network can be    formed-   and R¹ is a reactive organic group which is covalently bondable to    the organic oligomer and/or polymer,-   R² and R³ independently of one another are each an organic group    which may be covalently bondable to the organic oligomer and/or    polymer,-   with the proviso that-   n, m and o are integers, with n+m+o=1-3 and n=1 to 3, m=0 to 2, and    o=0 to 2,-   and/or the general formula (II)    (R¹O)_(n)(R²O)_(m)(R³O)_(o)MX_((k-n-m-o))  (II)    where the organometallic compound has at least one hydrolyzable    group X after whose hydrolysis a covalent bond of organic network    former to the inorganic network can be formed, at least one organic    radical R¹ which is a reactive organic group which is covalently    bondable to the organic oligomer and/or polymer, and R² and R³    independently of one another may each be an organic group which may    be covalently bondable to the organic oligomer and/or polymer,    where-   k is the formal oxidation number of M,-   M is Al, Zr or Ti,-   n is an integer from 1 to (k−1),-   m is an integer from 0 to (k−2),-   o is an integer from 0 to (k−2), and-   where n+m+o is an integer from 1 to k−1.

By formal oxidation number is meant, in accordance with the invention,that aluminum can have the oxidation number III, zirconium the oxidationnumber II, III or IV, and titanium the oxidation number II, III or IV.Preferably both zirconium and titanium have the oxidation number IV.

According to one preferred development of the invention the reactivegroup R¹ or the reactive organic radical R¹ is polymerizable. Theradical R¹ may be polymerizable, for example, with further radicals R¹,so that the organic network former can be present as such in anoligomerized or polymerized form in the hybrid inorganic/organic layer.Alternatively the radical R¹ may be polymerizable with other monomers,so that the organic network former may be present in the hybridinorganic/organic layer in copolymerized form, in a polymer alsoconstructed from further monomers.

Particularly preferred as organic network formers are organofunctionalsilanes. They are able, after the hydrolysis of the hydrolyzable groupX, to attach to the inorganic network. As a result of the hydrolysis,the group X is generally replaced by an OH group, which then condenseswith OH groups of the inorganic network to form a covalent bond. Thegroup X here stands preferably for halogen, hydroxyl, alkoxy having 1-10C atoms, which may be straight-chain or branched, may have in the carbonchain, and mixtures thereof.

The organic network former attaches at least via the functional group R¹with or to the organic oligomer and/or polymer. R¹ is preferably areactive functional group.

The reactive, preferably polymerizable, organic radical R¹ preferablyhas one or more substituents selected from the group consisting ofamino, hydroxyl, thiol, epoxy, acrylate, methacrylate, vinyl, allyl,alkenyl, alkynyl, carboxyl, carboxylic anhydride, isocyanate, cyanate,ureido, and carbamate group, and mixtures thereof. The organic radicalR¹ is preferably connected to the central silicon atom via a covalentC—Si bond.

The radicals R² and R³ independently of one another are selected fromthe group consisting of H—, (C₁-C₄₀)-alkyl-, (C₁-C₄₀)-fluorinatedalkyl-, (C₁-C₄₀)-partially fluorinated alkyl-; (C₂-C₄₀)-alkenyl-,(C₂-C₄₀)-alkynyl-; (C₆-C₃₆)-aryl-, fluorinated (C₆-C₃₆)-aryl-, partiallyfluorinated (C₆-C₃₆)-aryl-; (C₇-C₄₀)-alkylaryl-, (C₇-C₄₀)-arylalkyl-,fluorinated (C₇-C₄₀)-alkylaryl-, partially fluorinated(C₇-C₄₀)-alkylaryl-; (C₈-C₄₀)-alkenylaryl-, (C₈-C₄₀)-arylalkynyl-, -;(C₈-C₄₀)-alkynylaryl-; (C₅-C₄₀)-cycloalkyl-, (C₆-C₄₀)-alkylcycloalkyl-,(C₆-C₄₀)-cycloalkylalkylsilanes each of which may be substituted byamino, hydroxyl, thiol, epoxy, acrylate, methacrylate, vinyl, allyl,alkenyl, alkynyl, carboxyl, carboxylic anhydride, isocyanate, cyanate,ureido, carbamate and/or ester group and may contain O, N, and S asheteroatoms in the carbon chains and carbon ring systems. The radicalsR² and R³ preferably have chain lengths with 3 to 20 carbon atoms, morepreferably with 5 to 18 carbon atoms. The radicals R² and R³ may bebranched and/or linear. In the case of alkyl chains, these chains may beinterrupted by heteroatoms such as O, S or N.

The organic group or the radical R¹ in any case has a reactivity whichallows covalent bonding of the organic oligomer and/or polymer.

The organic groups or radicals R² and/or R³ may also have a reactivitywhich allows covalent bonding of the organic oligomer and/or polymer. Incontrast to the organic group R¹ or the radical R¹, however, it is notnecessary for a covalent bond to the organic oligomer and/or polymer toform between the radicals R² and/or R³. Accordingly the radicals R²and/or R³ may also be nonreactive. More particularly the radicals R² andR³ are preferably nonpolymerizable under the applied reactionconditions. Thus it is preferred for the radicals R² and R³, in contrastto the radical R¹, to be unable to polymerize with one another and, moreparticularly under the applied reaction conditions, to be unable toreact with monomers to form a polymer.

Suitable organofunctional silanes are, for example, numerousrepresentatives of the products produced by Degussa (Untere Kanalstrasse3, D-79618 Rheinfelden) and sold under the trade name “Dynasylan”. Forexample, 3-methacryloyloxypropyltrimethoxysilane (Dynasylan MEMO) can beused to construct a (meth)acrylate or polyester, vinyltri(m)ethoxysilane(Dynasylan VTMO or VTEO) to construct a vinyl polymer,3-mercaptopropyltri(m)ethoxysilane (Dynasylan MTMO or 3201) forpolymerizational incorporation into rubber polymers,aminopropyltrimethoxysilane (Dynasylan AMMO) orN2-aminoethyl-3-aminopropyltrimethoxysilane (Dynasylan DAMO) toconstruct a β-hydroxyamine, or 3-glycidyloxy-propyltrimethoxysilane(Dynasylan GLYMO) to construct a urethane or polyether network.

Further examples of silanes with vinyl and/or (meth)acrylatefunctionalities are as follows: isocyanatotriethoxysilane,3-isocyanatopropoxytri-ethoxysilane, vinylethyldichlorosilane,vinylmethyl-dichlorosilane, vinylmethyldiacetoxysilane,vinyl-methyldiethoxysilane, vinyltriacetoxysilane,vinyltri-chlorosilane, phenylvinyldiethoxysilane,phenylallyl-diethoxysilane, phenylallyldichlorosilane,3-methacryl-oyloxypropyltriethoxysilane,methacryloyloxypropyltrimethoxysilane,3-acryloyloxypropyltrimethoxysilane,2-methacryloyloxyethyltri(m)ethoxysilane,2-acryloyl-oxyethyltri(m)ethoxysilane,3-methacryloyloxypropyltris(methoxyethoxy)silane,3-methacryloyloxypropyltris(butoxyethoxy)silane,3-methacryloyloxypropyltris(propoxy)silane,3-methacryloyloxypropyltris(butoxy)silane.

As organic network formers it is also possible to use suitableorganofunctional titanates, zirconates or aluminates, of the kindproduced, for example, by Kenrich Petrochemicals and offered under thetrade name Ken-React® (purchasable from Nordmann, Rassmann GmbH, Kajen2, 20459 Hamburg). More particularly the coupling reagents given in theKEN-REACT® Reference Manual Titanate, Zirconate and Aluminate CouplingAgents, 2^(nd) revised edition, Summer 1993, on pages 2 to 21 can beused for the most part as organic network formers. The disclosurecontent of pages 2 to 21 of the aforementioned KEN-REACT® referencemanual is hereby incorporated by reference.

The hydrolyzable or condensable group X of these organic network formersis preferably alkoxy, but alternatively hydroxyl or halogen. In the caseof alkoxy it is also possible for there to be a cyclic group attachedvia two oxygen atoms to the central atom M, such as oxoethylene orcycloneopentyl, for example. In this case the central atom M has onlytwo further substituents. The hydrolyzable group may also be part of acyclic unit attached coordinatively via further oxygen atoms to thecentral atom, and hence may not be eliminated from the molecule afterhydrolysis.

In the case of further forms there may be two organophosphito ligandsbonded coordinatively to the central atom. In this case there are fouralkoxy ligands attached to the central atom.

These Al—, Zr— or Ti-organic network formers may be present in the formof chelate complexes or coordination complexes. The ligands in that casemay contain heteroatoms, preferably N, S or O.

Examples of such organic network formers are (see KEN-REACT® ReferenceManual—Titanate, Zirconate and Aluminate Coupling Agents by Salvatore J.Monte): Isopropyldimethacryloylisostearoyltitanate(IV)(KR7),alkoxytrimethacryloyltitanate(KR 33DS), isopropyltri(N-ethylenediamino)ethyltitanate(IV)(KR 44), tris(2-propenoato-0)methoxyglycolytotitanate (KR 39DS),methacrylatotriisopropoxytitanate, methacryloyloxyethylacetoacetonatotriisopropoxytitanate,(2-methacryloyloxyethoxy)triisopropoxytitanate titanium(IV)2,2(bis2propenolatomethyl)butanolato tris(dioctyl)pyrophosphato-0 (LICA38J), methacryloyl-oxyethylacetoacetonatotri-n-propoxyzirconate,neopentyl(diallyl)oxy-tri(N-ethylenediamino)ethyl-zirconate(IV)(NZ 44),9-octadecenylacetoacetato-diisopropoxyaluminate.

The inorganic component of the hybrid layer is preferably composed ofmetal oxide and/or metal oxide hydrate and/or metal suboxide and/ormetal hydroxide, at least partially forming a two- or three-dimensionalnetwork with one another.

The inorganic fraction of the hybrid layer of metal oxide and/or metaloxide hydrate and/or metal suboxide and/or metal hydroxide and/or metalperoxide is preferably selected from the group consisting of silicon,aluminum, titanium, zirconium, cerium, chromium, manganese, antimony,zinc, boron, magnesium, iron, and their mixtures and alloys.

As starting compounds which act as inorganic network formers of theseoxides it is preferred to use alkoxides, hydroxides, and halides ofthese metals.

The inorganic network formers preferably possess the general formulaMX_(n)where X independently at each occurrence is an optionally hydrolyzableand/or condensable group from halogen, hydroxyl or alkoxy having 1-10 Catoms, it being possible for the alkoxy group in the carbon chain tohave heteroatoms, preferably O, S and/or N, in the carbon chain.

The metal M is preferably Si, Al, Ti, Zr, P, Fe, Mg, Mn, Sb, Cr, Znand/or Ce, with the proviso that,

-   if M is Sb(V),-   n is 5 and,-   if M is Si, Ti or Zr,-   n is 4 and,-   if M is Al, Ce, Fe(III), SB(III) or B,-   n is 3 and,-   if M is Zn, Fe(II) or Mg,-   n is 2.    Where M is Al, Ti, Zr or Fe it is also possible for X to stand for    chelating ligands such as acetylacetonates or acetoacetic esters,    for example.

It is preferred to use inorganic network formers in which M is Si, Al,Ti and/or Zr, and X is alkoxy groups having 1 to 6 C atoms, it beingpossible for the alkoxy group in the carbon chain to have heteroatoms,preferably O, S and/or N, in the carbon chain. It is particularlypreferred to use tetraalkoxysilanes, more particularly tetramethoxy-and/or tetraethoxysilanes, to construct an SiO₂ layer.

Metallic effect pigments, more particularly aluminum effect pigments,which have been provided with a hybrid layer of SiO₂ and acrylate and/ormethacrylate are mechanically very stable and very stable to gassing. Ithas emerged that these properties can be improved further if, whengenerating the inorganic network, as for example by hydrolysis oftetraethoxysilane, acrylosilane and acrylic monomer and/or methacrylicmonomer are added. With this approach there is on the one hand acoupling of acrylosilane to the SiO₂ network which forms, and on theother hand a polymerization of acrylic monomer and/or methacrylicmonomer, and also a polymerizational incorporation of the acrylic groupof the acrylosilane into the acrylic oligomer and/or polymer and/ormethacrylic oligomer and/or polymer constructed from acrylic monomersand/or methacrylic monomers.

The precipitation of purely inorganic coatings on metallic effectpigments from metallic starting compounds of this kind is typicallyaccomplished at specific pH levels. These and other typical reactionconditions, such as temperature or time, are known to the skilledworker.

If the precipitation of the metal oxide from suitable inorganic networkformer on the platelet-shaped substrate is carried out in the presenceof suitable monomers and, optionally, polymerization initiators and alsoorganic network formers, then it is possible at the same time in atargeted way to form an inorganic oxide network and an organic oligomerand/or polymer. The inorganic network and the organic oligomers and/orpolymers are preferably in mutual interpenetration. In the case of onepreferred development of the invention there is not only an inorganicnetwork but also an organic network of oligomers and/or polymers, whichare preferably in mutual interpenetration.

Depending on the reaction conditions, the proportions of the reactantsused, and the kinetics of the reactions that take place, the hybridinorganic/organic layer may be substantially homogeneous. It is alsopossible, however, for there to be small regions of inorganic networkand/or organic oligomer and/or polymer in the hybrid layer.

By organic oligomers in the hybrid layer are meant, in this invention,the concept which is customary in polymer chemistry: that is, thelinking of two to twenty monomer units (Hans-Georg Elias,“Makromoleküle”, 4^(th) Edition 1981, Huthig & Wepf Verlag, Basle).Polymers are linkages of more than twenty monomer units.

In view of the diversity of organic monomers and the use of differentmetal oxides or metal oxide mixtures, there is in principle a wide rangeof variation possibilities for the formation of a hybridinorganic/organic layer. Through the ratio of monomer concentration tothe concentration of the organic network formers it is possible to varythe average chain length of the organic segments. Thus it is possible toproduce coatings which endow the metallic effect pigments with tailoredproperties in a multiplicity of respects. The average chain length ofthe organic segments is 2 to 10 000, preferably 10 to 1000, and morepreferably 40 to 200 monomer units.

The organic oligomer and/or polymer in the hybrid layer may beconstructed by polymerization of suitable monomers. The monomers mayhave functionalities selected from the group consisting of amino,hydroxyl, thiol, epoxy, acrylate, methacrylate, vinyl, allyl, alkenyl,alkynyl, carboxyl, carboxylic anhydride, isocyanate, cyanate, ureido,carbamate, and ester group, and mixtures thereof.

In one preferred embodiment the hybrid inorganic/organic layer isimplemented using organic network formers for the covalent linking oforganic and inorganic networks and through polymerization of organicmonomers. Particular preference is given to using silanes containing(meth)acrylate functions, such as Dynasylan MEMO, for example, asorganic network formers, and methacrylates as monomers.

Suitable as monomers or reactive oligomers or polymers are, moreparticularly, crosslinking (meth)acrylates, i.e., polyfunctional(meth)acrylates. Examples of such compounds are:

tetraethylene glycol diacrylate (TTEGDA), triethylene glycol diacrylate(TIEGDA), polyethylene glycol-400 diacrylate (PEG400DA),2,2′-bis(4-acryloyloxyethoxy-phenyl)propane, ethylene glycoldimethacrylate (EGDMA), diethylene glycol dimethacrylate (DEGDMA),triethylene glycol dimethacrylate (TRGDMA), tetraethylene glycoldimethacrylate (TEGDMA), butyl diglycol methacrylate (BDGMA),trimethylolpropane trimethacrylate (TMPTMA), 1,3-butanedioldimethacrylate (1,3-BDDMA), 1,4-butanediol dimethacrylate (1,4-BDDMA),1,6-hexanediol dimethacrylate (1,6-HDMA), 1,6-hexanediol diacrylate(1,6-HDDA), 1,12-dodecanediol dimethacrylate (1,12-DDDMA), neopentylglycol dimethacrylate (NPGDMA), particular preference is given totrimethylolpropane trimethacrylate (TMPTMA).

These compounds are available commercially from Elf Atochem DeutschlandGmbH, D-40474 Düsseldorf, Germany, or Rohm & Haas, In der Kron 4, 60489Frankfurt/Main, Germany.

Noncrosslinking (meth)acrylates can also be used as monomers forconstructing the organic component, i.e., the organic oligomer and/orpolymer, of the hybrid layer. Depending on further functional groups ofthese (meth)acrylates it is possible in turn to enable a very widediversity of variation possibilities for the chemical composition andhence also for the performance properties of the metallic effectpigments provided with a hybrid layer. Also suitable are mixtures ofcrosslinking and monofunctional vinyl and/or (meth)acrylate monomers.

Examples of monofunctional (meth)acrylates are: lauryl (meth)acrylate,allyl (meth)acrylate, propyl (meth)acrylate, isobornyl methacrylate, andhydroxyl-ethylimidazoline methacrylate.

These compounds are likewise available commercially from Elf AtochemDeutschland GmbH, Uerdingerstr. 4 D-40474 Dusseldorf or from Rohm &Haas, In der Kron 4, 60489 Frankfurt/Main, Germany.

The polymerization of vinyl-functional and/or (meth)acrylate-functionalmonomers when constructing the hybrid inorganic/organic layer can beaccomplished by thermal polymerization. Preference is given to the useof polymerization initiators, preferably free-radical initiators. Theseare commercially customary, generally organic or inorganic peroxides ordiazonium compounds. Examples of such compounds are:

Acetylcyclohexanesulfonyl peroxide, bis(2,4-dichloro-benzoyl) peroxide,diisononanyl peroxide, dioctanoyl peroxide, diacetyl and dibenzoylperoxide; peroxy-dicarbonates (e.g., diisopropyl peroxydicarbonate,di-n-butyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate,dicyclohexyl peroxydicarbonate), alkyl peresters (e.g., cumylperneodecanoate, t-butyl perneodecanoate, t-amyl perpivalate, t-butylper-2-ethyl-hexanoate, t-butyl perisobutyrate, t-butyl perbenzoate),dialkyl peroxides (e.g., dicumyl peroxide, t-butyl cumyl peroxide,2,5-dimethylhexane-2,5-di-t-butyl peroxide,di(t-butylperoxyisopropyl)benzene, di-t-butyl peroxide, or2,5-dimethylhex-3-yne-2,5-di-t-butyl peroxide), perketals (e.g.,1,1′-bis(t-butylperoxy)-3,3,5-trimethylcyclohexanone peroxide, methylisobutyl ketone peroxide, methyl ethyl ketone peroxide, acetylacetoneperoxide), alkyl hydroperoxides (e.g., pinane hydroperoxide, cumenehydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide or t-butylhydroperoxide), azo compounds (e.g., 4,4′-azobis(4-cyanovaleric acid),1,1′-azobis(cyclohexanecarbonitrile), 1,1′-azobis(isobutyroamidine)dihydrochloride, 2,2′-azobis(isobutyronitrile), or persulfates such assodium peroxodisulfate and potassium peroxodisulfate. Preference isgiven to 2,2′-azobis(isobutyronitrile).

These compounds are available commercially from Aldrich Chemie, D-89552,Steinheim.

The polymerization of vinyl-functional and/or (meth)acrylate-functionalmonomers when constructing the hybrid inorganic/organic layer may alsobe carried out, furthermore, by an ATRP (atomic transfer radicalpolymerization), the so-called living free-radical polymerization. Herethe organic network former used is preferably a silane compound in whichR¹ has been provided terminally with an alkyl halide, preferably analkyl bromide with an ester group in α position. Also added in this caseare Cu(I) salts, optionally in a mixture with Cu(II) salts or metallicCu, and also suitable ligands which complex the copper compounds.Further details on this are found in DE 198 38 241 A1.

When epoxysilanes are used as organic network formers, they can bereacted with polyfunctional amines as crosslinkers. Further variationpossibilities are also obtained when using polyfunctional epoxycompounds. Combinations of polyfunctional epoxy compounds andpolyfunctional amino compounds may of course also be used when usingamino-functional silanes as coupling reagents.

Examples of polyfunctional amines suitable for such reactions andavailable commercially include the following:3,3-dimethyl-4,4-diaminodicyclohexylmethane, ethylenediamine,triethylenetetramine, meta-xylylene-diamine, N-aminoethylpiperazine,2-methyl-1,5-penta-methylenediamine, 1,2-diaminocyclohexane orisophorone-diamine.

Examples of suitable polyfunctional epoxy compounds availablecommercially include the following: 1,4-butanediol diglycidyl ether,glycerol triglycidyl ether, neopentyl glycol diglycidyl ether,pentaerythritol polyglycidyl ether, 1,6-hexanediol diglycidyl ether,polypropylene glycol diglycidyl ether or trimethylolpropane triglycidylether. These polyfunctional amines and epoxy compounds are availablecommercially from the company UPPC: (U. Prümmer Polymer-Chemie GmbH;Mühlhalde 8 in D-88487 Baltringen).

In a further embodiment of the invention the organic network is notprepared during the reaction. Instead the organic component usedcomprises reactive organic oligomers and/or polymers which possessreactive groups which permit attachment to the oxide network via the atleast one group R¹ of the organic network formers. In order to ensure aneffective reaction with, more particularly, the group R¹ of the organicnetwork formers, the oligomer and/or polymer can also be reacteddirectly with the organic network former before incorporation into thehybrid layer. For that purpose the oligomers and/or polymers aredissolved in a suitable solvent, organic network formers are added, andthe components are reacted. The organic oligomers and/or polymerscoupled with the organic network former can then be reacted with themetal oxide-forming compounds used to generate the inorganic network, toform the hybrid inorganic/organic layer.

Examples of reactive organic oligomers and/or polymers which can beincorporated directly into the inorganic network that forms, during thereaction, include the following: silicones terminated with silanol ormethoxy groups, silane-modified polyethyleneimines or polybutadienes,polyarylalkylsilasesquioxanes or amino-silane-modified polyethyleneoxide urethanes. For these compounds, particularly low molecular weightsfrom a range from 100 to 1000 g/mol are preferred. Low molecular weightcompounds of this type have a particularly large number of linkage sitesto the inorganic oxide network, and so produce more homogeneouslydistributed hybrid inorganic/organic layers.

Examples of commercially available compounds of this kind are:

reactive silicones such as 1,7-dichlorooctamethyltetra-siloxane,diphenylsiloxanes terminated with silanol groups, dimethylsiloxane anddiphenylsiloxane copolymers terminated with silanol and/or methoxygroups, polytrifluoropropylmethylsiloxane terminated with silanolgroups, trimethoxysilylpropyl-substituted polyethyleneimine,dimethoxymethylsilylpropyl-substituted polyethyleneimine,triethoxysilyl-modified polybutadiene, dimethoxymethylsilyl-modifiedpolybutadiene, vinylmethoxysiloxane oligomer,(N-triethoxysilylpropyl)-O-polyethylene oxide urethane andpoly(trimethylsilylpropyne) (all available from, for example, ABCR GmbH& Co. Postfach 210135, Hansastr. 29c, D-76151 Karlsruhe, Germany). Afurther example are silane-modified phenol-formaldehyde oligomers, ofthe kind produced and sold as resoles or novolaks by Bakelite AG(Gennaer Straβe2-4, D-58642 Iserlohn-Letmathe).

In a further embodiment of the invention it is also possible as reactiveoligomers and/or polymers to use compounds which possess reactive,preferably polymerizable, functional groups. The polymerizablefunctional groups can be prepared, for example, by a subsequent reactionof the oligomer and/or polymer (as for example by means of apolymer-analogous reaction). These reactive oligomers/polymers reactwith the functional organic groups of suitable organic network formersand in that way are bonded covalently to or in the inorganic oxidenetwork.

These reactive oligomers and/or polymers may be reactive polymers fromthe group of the polyacrylates, polymethacrylates, polyethers,polyesters, polyamines, polyamides, polyols, polyurethanes, andpolyolefins.

Organic oligomers and/or polymers which can be incorporated via suitablefunctional groups directly into the hybrid layer are preferably thosewhich possess polymer-chemically compatible functional groups, such asthe organic network formers. Thus, in the case of a silane containingepoxy groups, it is preferred to use an epoxy resin or a resincontaining amino groups; in the case of silanes containing (meth)acrylicgroups it is preferred to use (meth)acrylates, etc. Where the reactionof the functional groups of the organic oligomers/polymers with thereactive groups R¹ of the organic network formers takes place by way ofcondensation mechanisms or addition mechanisms, the functional groupsare preferably matched to one another accordingly. For example,epoxide-containing polymers can be reacted particularly well withepoxy-functionalized or amino-functionalized silanes. In this way thepolymers are modified by alkoxysilanes and hence can be reacted verywell together with, for example, tetraalkoxysilanes to give hybridinorganic/organic layers.

One example of a prepolymer/preoligomer which can be used in this way isthe epoxy resin D.E.R: 330 (Dow Corning; Rheingaustr. 53 in D-65201Wiesbaden, Germany). Further examples are(epoxycyclohexyl-ethyl)methylsiloxane-dimethylsiloxane copolymer,amino-propylmethylsiloxane-dimethylsiloxane copolymer from ABCR, andalso polybutadiene-poly(2,3-epoxy)butadiene copolymer (available fromAldrich, D-89552 Steinheim, Germany).

In a further embodiment of the invention the formation of organicoligomer and/or polymer takes place within an inorganic oxide, bycausing only the functional groups of the organic network formers topolymerize with one another. In this way, for example, organic networkformers in which the reactive, preferably polymerizable, group R¹ arepreferably methacrylate, acrylate or vinyl groups are oligomerized orpolymerized by addition of suitable polymerization initiators. It isalso possible for epoxide-containing silanes, for example, to react withone another prior to incorporation into an oxide network, to formoligomeric/polymeric polyether units. A mixture of suitableepoxy-functionalized and amino-functionalized silanes can react at leastpartly, prior to incorporation into the hybrid inorganic/organic layer,to form oligomeric/polymeric β-hydroxyamines, and in this way mayalready form a quasi-two-dimensional organic network. These silanemixtures can then be reacted with the resultant oxide network to form ahybrid inorganic/organic layer.

Hybrid inorganic/organic layers formed in this way may, however, have alower degree of polymerization in the context of the organic componentthan if, additionally, organic monomers are copolymerized, i.e., areadded additionally during the polymerization.

Preference is therefore given, in a further embodiment of the invention,to the additional use of organic monomers to construct the organicnetwork.

In order to be able reliably to utilize not only the advantageouseffects of the organic oligomer and/or polymer but also those of theinorganic oxide network, the organic fraction in the hybridinorganic/organic layer applied to a platelet-shaped substrate ispresent preferably in a range from 4% to 85% by weight, more preferably5% to 75% by weight, and with particular preference 10% to 50% byweight, the % by weight figure being based on the weight of the overallhybrid layer.

Below 4% by weight of the organic component, the advantageous, i.e.,elasticity-enhancing effects of the organic oligomer and/or polymer arebarely active. On the other hand, above 85% by weight of organicfraction in the hybrid layer, the advantageous, i.e., theabrasion-resistance-enhancing effects of the inorganic component arelost.

These amounts of the organic components can be determined analyticallyin a simple way, on the basis of the C content of the effect pigment.

In the case of complex layer constructions with further purely organicor inorganic layers, it is advisable, for the analysis of such layers,to employ sputtering techniques in combination with surface-sensitiveanalytical methods such as ESCA and/or SIMS.

In order to develop the advantageous effects of the hybridinorganic/organic layer in the sense of mechanical stabilization and/orboosted hydrophobization, the average thickness of the hybrid layer ispreferably at least 2 nm, more preferably at least 3 nm, and withparticular preference at least 10 nm. Below 2 nm the advantageouseffects of the hybrid inorganic/organic layer become barely perceptible.

The hybrid inorganic/organic layer is stabilized mechanically even stillat very high layer thicknesses. The thickness of the hybridinorganic/organic layer is typically located within a range from about10 nm to 50 nm. The advantageous effects, however, are still presenteven at a maximum layer thickness of 800 nm, preferably 700 nm, and verypreferably 600 nm. Layer thicknesses above these ranges have the effectoverall of producing an excessive increase in the thickness of themetallic effect pigments. In that case the orientation capacity of themetallic effect pigments in the application medium, which is critical tothe formation of optical effect, is increasingly restricted.Furthermore, with very thick coatings, the opacity of the pigments isadversely affected.

Viewed over the thickness of the layer, the two components of the hybridinorganic/organic layer may be present in homogeneous distribution orelse in inhomogeneous distribution, such as, for example, in the form ofa gradient distribution, such that the proportion of the two componentsalters along the layer thickness. In the case of inhomogeneousdistribution of the individual components, the abovementioned limits tothe composition of the hybrid layer apply for the average value alongthe thickness of the hybrid layer. In accordance with the invention,however, a substantially homogeneous, and preferably homogeneous,distribution of inorganic network and organic oligomer and/or polymer ispreferred.

The organic oligomers and/or polymers may for example also be present atleast partly in the form of nanoparticles in the inorganic network, toform the hybrid inorganic/organic layer. An alternative possibility isfor the inorganic oxide component to be present at least partly in theform of nanoparticles in the organic oligomer and/or polymer, to formthe hybrid inorganic/organic layer. In accordance with a further variantof the invention the hybrid inorganic/organic layer in the nanoscalerange has a substantially homogeneous construction, and so the formationof inorganic nanoparticles in a substantially organic environment ofoligomer and/or polymer, or of organic nanoparticles in the form ofoligomer and/or polymer in an inorganic environment, is a relativelyinfrequent occurrence. A homogeneous construction is obtained inparticular when using a high fraction of organic network formers whenproducing the hybrid inorganic/organic layer.

The platelet-shaped substrate is generally composed of commerciallyavailable metallic effect pigments. These encompass pure metal pigments,coated metal pigments, and interference pigments comprising metals.

Platelet-shaped substrates are those having a form factor (ratio of theaverage of the longitudinal extent to the average thickness) of 3 to 10000, preferably of 5 to 5000, and very preferably of 10 to 4500. Thesize relationships of the platelet-shaped substrates are characterizedby the average (d₅₀ value) of the cumulative distribution curve, of thekind typically measured by laser diffraction methods. Preference isgiven in this context to sizes, i.e., longitudinal extents, having a d₅₀of 2 to 2000 μm, more preferably of 3 to 1000 μm, with furtherpreference of 4 to 200 μm, and with very particular preference of 5 to100 μm.

The metallic effect pigments are composed of materials such as aluminum,copper, iron, zinc, tin, titanium, chromium, silver, cobalt, nickel,antimony, magnesium, zirconium, and silicon, and their alloys. Preferredalloys are gold bronzes (brass), and in addition it is likewise possibleto use steel and stainless steel pigments. In the case of pure metals,i.e., of metals with an ultrapure fraction >98% by weight, aluminum,copper, and iron are preferred.

Particularly preferred are platelet-shaped substrates of aluminum, brass(gold bronzes), and also iron pigments produced from (reduced) carbonyliron pellets, of the kind described in accordance with the teaching ofDE 101 14 446 A1.

These substrates possess longitudinal extents of 1 to 1000 μm,preferably of 5 to 100 μm. The average thicknesses are 30 to 2000 nm,preferably 70 to 800 nm, and more preferably 150 to 500 nm. Very thinaluminum pigments produced by wet grinding processes are described in DE103 15 755 A1, for example, which is hereby incorporated by reference.

The metal pigments can be produced both by conventional technologiessuch as the wet or dry grinding of corresponding metal pellets, or byPVD (physical vapor deposition) belt coating processes, of the kinddescribed in U.S. Pat. No. 4,321,087, for example. In the latter casethe metal pigment, after it has been detached from the belt andmechanically comminuted to pigments, can be provided with a hybridinorganic/organic layer. In this way these pigments can be mechanicallystabilized and protected from corrosive influences.

Further suitable platelet-shaped substrates are coated metal pigments.In this context mention may be made, for example, of aluminum pigmentscoated with iron oxide (trade name: “Paliocrom®”, BASF, Ludwigshafen,Germany), chromated aluminum pigments (trade name: “Hydrolux”, Eckart),oxidized aluminum pigments (trade name: “Aloxal”, Eckart), aluminumpigments coated with titanium oxide, and iron pigments provided withoxide layers [DE 101 14 445 A1].

Particularly preferred are aluminum pigments coated with iron oxide(trade name: “Paliocrom®”). These are metal pigments which have beencoated with a purely inorganic iron oxide layer.

Pigments with very high weathering stability are obtained by usingchromated aluminum pigments as a substrate. These pigments can be usedin exterior architecture as IR-reflecting pigments. In this case thehigh reflection of aluminum pigments in the infrared range is utilizedto produce heat-insulating external architectural coatings. When used inexternal architecture, however, the pigments must also withstand extremeconditions. It has surprisingly emerged that the metallic effectpigments of the invention with a hybrid inorganic/organic layer areoutstandingly suitable for use in protecting facades.

In a further development in accordance with the invention theorganically/inorganically modified layer is additionally modifiedthrough the use of network modifiers. In contrast to the organic networkformers, network modifiers do not form organic oligomers/polymers, andpolymerize neither with added organic monomers nor with one another.

Organic network modifiers are reagents which contain not only at leastone hydrolyzable group but also at least one organic group, which neednot necessarily, however, be reactive or polymerizable. Organic networkmodifiers are preferably compounds of the general formula (III)R¹ _(n)R² _(m)R³ _(o)SiX_((4-n-m-o))  (III)

-   where X is a hydrolyzable group after whose hydrolysis a covalent    bond of organic network modifier to the inorganic network can be    formed,-   and R¹, R², and R³ independently of one another are each a    nonreactive organic group, with the proviso that n, m and o are    integers, where n+m+o=1−3 and n=1 to 3, m=0 to 2, and o=0 to 2,-   and/or of the general formula (IV)    R⁴ _(p)MX_((k-p))  (IV)    where the compound has at least one hydrolyzable group X after whose    hydrolysis a covalent bond of organic network modifier to the    inorganic network can be formed, and has at least one nonreactive    organic-   radical R⁴, where-   k is the formal oxidation number of M,-   M is Al, Zr or Ti, and-   p is an integer from 1 to (k−1).

The hydrolyzable or condensable group X of the organic network modifiersis preferably selected from the group consisting of halogen, hydroxyl oralkoxy having 1-10 C atoms, which may be linear or branched.

The organically functionalized groups R¹, R² and R³ are preferablyselected from the group consisting of H, alkyl, alkenyl, alkynyl, aryl,alkylaryl, arylalkyl, alkenylaryl, arylalkynyl, alkynylaryl, cycloalkyl,alkylcycloalkyl, cycloalkylalkyl, amino, hydroxyl, thiol, mercaptan,fluorinated alkyl, partly fluorinated alkyl, (partly) fluorinated aryl,(partly) fluorinated alkylaryl, acrylate, methacrylate, vinyl, epoxy,carboxyl, and ester group. The radicals R¹, R², and R³ preferably havechain lengths with 3 to 20 carbon atoms, more preferably with 5 to 15carbon atoms. The radicals R¹, R², and R³ may be cyclic, branched and/orlinear and may contain heteroatoms such as O, S, and N in the carbonchain or in the carbon ring system. With regard to the length of thefunctional groups R¹, R², and R³, reference is made accordingly to theobservations relating to the organic network former.

The above-recited functionalities of the organic network modifiers arein some cases identical with those also used as organic network formers.The difference is that in this case the functionalities are not intendedto react with one another or with organic monomers or polymers. This isthe case when, in terms of their chemical reactivity, thefunctionalities of R¹, R², and R³ are different from the functionalitiesof the monomers or else from those of the organic oligomers and/orpolymers. Accordingly, through a choice of network modifier and suitablemonomers, the reaction can be controlled in such a way that there is noreaction of network modifiers with one another or with the monomers.

If, for example, exclusively a mixture of organofunctional silanes isused to construct the organic component, i.e., the organic oligomerand/or polymer, of the hybrid layer, then all organofunctional silaneswhose functional groups do not react with one another function asorganic network modifiers.

Organofunctional silanes suitable as pure organic network modifiers are,in particular, compounds without functionalities having pronouncedchemical reactivity. These are, in particular, (C₁-C₄₀)alkyl,(C₆-C₃₆)aryl, and also perfluorinated or partly fluorinated(C₁-C₄₀)alkyl and/or (C₆-C₄₀)aryl functionalities as radicals R¹, R²,and R³. The alkyl radicals may be linear, branched or cyclic. Examplesare:

propyltri(m)ethoxysilane, octyltri(m)ethoxysilane,dodecyltri(m)ethoxysilane, octadecyltri(m)ethoxysilane,phenyltri(m)ethoxysilane, diphenyldi(m)ethoxysilane,perfluorooctyltri(m)ethoxysilane, 1-,1-,2-,2-,3-,3-,4-,4-fluorooctyltri(m)ethoxysilane, 5-,5-,6-,6-,7-,7-,8-,8-,8-fluorooctyltri(m)ethoxysilane,1H—,1H—,2H—,2H-per-fluorooctyltriethoxysilane (Dynasylan F 8261).

Examples of organic network modifiers with Ti, Zr or Al as central atomare (see Ken-React Reference Manual-Titanate, Zirconate and AluminateCoupling Agents by Salvatore J. Monte, expanded edition Summer 1993):

isopropyltriisostearyltitanate(IV) (KR TTS),isopropyl-tri(dioctyl)phosphatotitanate(IV) (KR 12),isopropyl-tri(dodecyl)benzenesulfonyltitanate(IV) (KR 9S),iso-propyltri(dioctyl)pyrophosphatotitanate(IV) (KR 38S),di(dioctyl)phosphatoethylenetitanate(IV) (KR 212),di(dioctyl)pyrophosphatoethylenetitanate(IV) (KR 238S),di(dioctyl)pyrophosphatooxoethylenetitanate(IV) (KR 138S),diisobutyl(stearyl)acetoacetylaluminate (KA 301).

With further developments of the invention the substrates may first beprovided with one or more coatings which are either only inorganic oronly organic in nature, before the hybrid layer is applied. Thepreparation of such purely inorganic or purely organic layers is verywell known to the skilled worker.

In additional developments of the invention further purely inorganicand/or purely organic coatings may be applied to the hybridinorganic/organic layers. The preparation of such coats is likewise verywell known to the skilled worker.

The thicknesses of the purely inorganic or organic layers are preferablybetween 3 and 1000 nm, more preferably between 4 and 800 nm, withparticular preference between 5 and 500 nm, and with very particularpreference between 7 and 50 nm.

“Purely inorganic” layers here are layers having an organic fraction ofbelow 4% by weight. “Purely organic” layers are layers having aninorganic fraction of below 4% by weight. The above amounts in % byweight refer in each case to the weight of the respective layer.

The reaction conditions for the coating with purely inorganic or organiclayers before or after the application of the hybrid layer may possiblydiffer from those needed for forming the hybrid layer. Thus, forexample, the reaction temperature, the solvent or the pH may be changed.This may, where appropriate, require termination of the reaction beforeor after the precipitative application of the hybrid inorganic/organiclayer to the substrate, and the processing of the precursor, by means offiltration and drying under vacuum, for example. Preferably, however,coating with a purely inorganic layer and/or a purely organic layer iscarried out in the same medium as the coating with the hybridinorganic-organic layer, as a one-pot reaction.

It has been found, surprisingly, that the performance advantages of theincreased mechanical stability and the improved corrosion protection ofthe hybrid inorganic/organic layer are largely independent of whetherthere are further purely organic or purely inorganic layers presentbetween substrate and hybrid layer and/or on the hybrid layer itself. Itcan be of advantage when coating first to begin only with the inorganiccomponent. In this way it is possible to bring about better adhesion ofthe subsequent hybrid layer on the substrate. This is the caseespecially when the hybrid layer has very hydrophobic constituents, suchas organic fluorinated functionalities, for example.

A further coating of the hybrid layer with a, for example, pure oxidelayer is likewise advantageous. In certain circumstances a desiredsurface modification can be carried out more effectively on this oxidelayer than may be the case on the hybrid layer. This is especially sowhen the hybrid layer has very hydrophobic constituents and/or has avery high fraction of organic oligomer and/or polymer (e.g., >20% byweight).

In the case of a purely inorganic coating of metal oxides/hydroxides,the latter are selected from oxides, metal oxide hydrates, suboxidesand/or hydroxides of the elements from the group consisting of silicon,titanium, aluminum, zirconium, iron, copper, tin, cobalt, chromium,cerium, nickel, tin, vanadium, tantalum, yttrium, molybdenum, tungsten,and mixtures thereof. The precipitation of such a layer on metalliceffect pigments is very well known to the skilled worker. It proceeds inaccordance with the following general process:

-   (a) The platelet-shaped substrate is dispersed in a solvent and the    suspension is brought to reaction temperature.-   (b) Then one or more metal compounds of the formula MX_(n) are    added, a suitable pH range is set by addition of suitable acids or    bases, and, where appropriate, water is added. M, X and n here have    the same definitions as given above. Furthermore, M may additionally    be Cu, Co, Ni, Sn, V, Ta, Y, Mo and/or W. Where appropriate the    oxide layer can also be precipitated onto the hybrid    inorganic/organic layer in the same solvent, following the    deposition of the hybrid inorganic/organic layer.-   (c) Finally the reaction is continued for a certain time at the    reaction temperature and then cooled to room temperature. The    product is subsequently separated from the solvent.

A purely organic coating may be composed, for example, ofpoly(meth)acrylates, polyesters, polyurethanes, polyols, polyethers orpolyamides. The precipitation of such a layer on metallic effectpigments is likewise very well known to the skilled person. It proceedsin accordance with the following general process:

-   (a) The platelet-shaped substrate is dispersed in a solvent and the    suspension is brought to reaction temperature.-   (b) Then one or more organic monomers and, where appropriate,    polymerization initiators are added, possibly dropwise, to form an    organic polymer layer. Prior to the application of the organic    polymer layer it is possible, optionally, to add a suitable adhesion    promoter, in order to ensure better attachment of the polymer to the    surface of the metallic effect pigment [in the way known from DE 40    30 727].-   (c) The coated pigment, finally, is separated from the reaction    medium.

In further developments of the invention the metallic effect pigmentswhich have a hybrid inorganic/organic layer may be provided with asurface modifier. Examples of such surface modifiers are already knownfrom DE 198 20 112. This surface modifier can be used to make themetallic effect pigments compatible, in terms of their performanceproperties, with the particular application medium used: for example, avarnish or a printing ink.

An improvement in the corrosion protection properties of a coating or inthe mechanical stabilization cannot, however, be achieved solely bymeans of a surface modification.

Where appropriate, the addition of the surface modifier may also takeplace following the precipitation of the hybrid inorganic/organic layer,or the precipitation of one or more further inorganic layers, in thesame solvent. It is also possible to dissolve the surface modifier in asuitable solvent and then apply it in a mixer to the metallic effectpigments. Another possibility is to apply the surface modifier, whereappropriate in dry form, to the metallic effect pigments of theinvention, such as by means of spray drying, for example.

The process of the invention for producing metallic effect pigments witha hybrid inorganic/organic layer comprises, in one variant, thefollowing steps:

-   (a) providing a reaction mixture of platelet-shaped metallic    substrates in a liquid phase,-   (b1) adding at least one inorganic network former to the reaction    mixture from step (a),-   (c1) hydrolyzing and/or condensing the inorganic network former    added in step (b1),-   (d1) adding at least one reactive organic network former and at    least one reactive organic component before, during and/or after the    hydrolysis and/or condensation of step (c1),    or-   (b2) adding at least one reactive organic network former and at    least one reactive organic component to the reaction mixture from    step (a),-   (c2) adding at least one inorganic network former to the reaction    mixture from step (b2),-   (d2) hydrolyzing and/or condensing the inorganic network former    added in step (c2),    and-   (e) reacting hydrolyzed and/or condensed inorganic network former    with the reactive organic network former and also with the reactive    organic component, with simultaneous and/or subsequent deposition of    a hybrid inorganic/organic layer to the platelet-shaped substrates,    the hybrid layer having at least partly an inorganic network that    has one or more inorganic oxide components, and at least one organic    component, the organic component being at least partly an organic    oligomer and/or polymer which is at least partly covalently bonded    to the inorganic network,-   (f) optionally separating the platelet-shaped substrates coated in    step (e) from the reaction mixture.

According to one variant, therefore, the process of the invention can becarried out on the basis of steps (a), (b1), (c1), (d1), (e), and (f),or on the basis of steps (a), (b2), (c2), (d2), (e), and (f).

The at least one reactive organic component is preferably added in theform of reactive polymerizable organic monomers, oligomers and/orpolymers.

Furthermore it is preferred to add at least one reactive oligomer and/orpolymer as the reactive organic component.

According to one preferred development of the process of the inventionthe reactive oligomer and/or polymer is selected from the groupconsisting of polyacrylates, polymethacrylates, polyethers, polyesters,polyamines, polyamides, polyols, polyurethanes, polyolefins, andmixtures thereof, and for activation is optionally reacted with anorganic network former prior to the addition to the reaction mixture orto the liquid phase.

It is further preferred for the reactive organic component to be formedprior to addition, by reacting one or more different organic networkformers with reactive groups R¹ with one another, optionally withaddition of polymerization initiators, and subsequently carrying outaddition.

Preferably the reactive organic oligomer and/or polymer is selected fromthe group consisting of silanol- and/or methoxy-terminated silicones,trialkoxysilane-modified polyethyleneimines,polyarylalkylsilasesquioxanes, aminosilane-modified polyethylene oxideurethanes.

According to one further variant of the process of the invention thereactive organic oligomer and/or polymer is selected from the groupconsisting of polyacrylates, polymethacrylates, polyethers, polyesters,polyamines, polyamides, polyols, polyurethanes, and polyolefins, theseoligomers and/or polymers possessing reactive, nonpolymerized functions.

In one further variant of the process of the invention, before, duringand/or after the addition of the reactive organic component,additionally at least one organic network modifier is added.

For the rest, with regard to the process of the invention, reference ismade accordingly to the observations relating to the metallic effectpigments of the invention.

As the liquid phase it is possible to use aqueous and/or organicsolutions. Preference is given to organic solutions in the form ofalcoholic solutions which possess a water content of 1% to 80% byweight, preferably 2% to 20%, and more preferably 3% to 10% by weight. Awater content of at least 1% by weight is needed in order to hydrolyzethe organic and inorganic network formers. The % by weight figure isbased in each case on the total weight of the solvent.

Organic solvents which can be used are all customary solvents such asalcohols, ethers, ketones, esters, glycols or hydrocarbons or mixturesthereof. Preferred alcohols used are, for example, methanol, ethanol,n-propanol, isopropanol, n-butanol or 2-butanol or mixtures thereof.

Steps (b) to (e) of the coating reaction take place at reactiontemperatures in a range from approximately 0° C. to approximately 100°C., preferably from approximately 10° C. to approximately 80° C. Thereaction temperatures are limited by the boiling point of the solvent orsolvent mixture that is used.

The pH in steps (b) to (e) is located within a range from 3 to 12,preferably from 7 to 10. The pH must not be too acidic or alkaline,since the metal pigments are corroded by the water used for thereaction. Preference is therefore given to neutral to slightly alkalinepH levels.

After the optional step (f) it is possible for the inventively coatedmetal pigments to be subjected to a size classification, as by sieving,for example. Moreover, they can be dried out in a suitable assembly.After the pigments have been separated from the reaction mixture it ispossible to switch the solvent, adding a solvent other than that usedfor the reaction to the dried pigment powder. In this way pastes can beprepared which have a metal pigment content of 50% to 90% by weight,preferably of 60% to 75% by weight, the % by weight figure being basedon the weight of the paste.

The inventively coated metallic effect pigments find use in varnishes,paints, printing inks, powder coating materials, plastics, securityprinting inks, glass, ceramic, architectural coatings or cosmetics.

The pigments of the invention were investigated for their gassingstability following severe mechanical loading in a laboratory kneader.

For these investigations the following test methods were used:

Yellow Iron Oxide Gassing Test

38.8 g of metal pigment powder were combined with about 40 g of acommercially available basecoat varnish and 41 g of a yellow aqueoustinting paste containing iron oxide pigments. Then 240 g of basecoatvarnish were added and the mixture was dispersed for 30 minutes using atoothed dissolver disk (œ50 mm) at 2000 rpm. The aqueous paint was thenintroduced into a wash bottle, which had been given a twin-chamber gasbubble counter, and was heated at 40° C. The volume of gas evolved couldbe read off from the level, in mm, in the twin-chamber gas bubblecounter. The gas level was read off after 7, 14, 21, and 28 days. Thetest was passed when no more than 20 mm of hydrogen were evolved after28 days.

Laboratory Kneader Treatment

100 g of pigment were made up with isopropanol to form a paste with asolids content of 65%. This paste was kneaded in a high-performancelaboratory kneader (from IKA) at room temperature for 5 minutes. Thehigh viscosity of these metallic effect pigment pastes allows extremelyhigh shearing forces to act on the pigments by means of the mechanicalinfluence of the duplex kneading vanes. Subsequently the metallicpigment paste thus treated was subjected to the gassing test describedabove, for which the solvent content of the paste is taken into accountwith regard to the initial mass.

The working examples which follow are intended to illustrate theinvention, but without restricting it.

EXAMPLES Example 1

95 g of Paliocrom L 2000 (BASF) are dispersed in 310 ml of isopropanoland the dispersion is heated to the boiling point. Then 9 g oftetraethoxysilane are added and, a short time later, 9 g of H₂O.Subsequently a 25% strength aqueous NH₄OH solution is introduced via anautomatic metering unit over a period of 3 h at a rate such that, duringthis time, a pH of 8.7 is attained and maintained. 1 h after thebeginning of this metered addition, solution A (see below) is alsometered in continuously using a laboratory automatic metering unit(STEPDOS from IKA) over a period of 85 min. 5 min after the beginning ofthis feed, the polymerization is initiated by adding a spatula tip of2,2′-azobis(isobutyronitrile) (AIBN). The reaction mixture is then leftwith stirring at 88° C. for 4 h. Subsequently a mixture of 0.8 g ofDynasylan OCTEO and 0.5 g of Dynasylan AMMO is added. The reactionmixture is stirred overnight and filtered the next day. The filtercakeis dried in a vacuum drying cabinet at 100° C. for 6 h.

Solution A: 0.59 g of Dynasylan MEMO and 2.51 g of trimethylolpropanetrimethacrylate (TMPTMA) in solution in 116 ml of ethanol.

Example 2

Preparation as in example 1, but using ethanol instead of isopropanol assolvent.

Example 3

Preparation as in example 1, but using the following solution B:

0.59 g of Dynasylan MEMO, 2.51 g of TMPTMA and 0.5 g of laurylmethacrylate in solution in 116 ml of ethanol.

Example 4

Preparation as in example 2, but using the following solution C:

0.59 g of Dynasylan MEMO, 2.51 g of TMPTMA and 0.5 g of ethylene glycoldimethacrylate (EGDMA) in solution in 116 ml of ethanol.

Example 5

Preparation as in example 1, but using the following solution D:

-   0.59 g of Dynasylan MEMO, 2.51 g of TMPTMA and 0.47 g of allyl    methacrylate in solution in 116 ml of isopropanol.

Example 6

Preparation as in example 2, but using the following solution E:

-   1.0 g of Dynasylan MEMO, 5.2 g of TMPTMA in solution in 116 ml of    ethanol.

Example 7

Preparation as in example 1, but using the following solution F:

-   1.0 g of Dynasylan MEMO, 9.8 g of TMPTMA in solution in 116 ml of    isopropanol.

Example 8

Preparation as in example 2, but without using2,2′-azobis(isobutyronitrile) (AIBN) as initiator, and using thefollowing solution G:

-   1.0 g of Dynasylan GLYMO, 2.0 g of 1,6-hexamethylene-diamine and 0.5    g of pentaerythritol polyglycidyl ether in solution in 116 ml of    ethanol.

Example 9

Preparation as in example 1, but without using2,2′-azobis(isobutyronitrile) (AIBN) as initiator, and using thefollowing solution H:

-   1.0 g of Dynasylan GLYMO, 2.0 g of 1,6-hexamethylene-diamine and 0.5    g of trimethylolpropane triglycidyl ether in solution in 116 ml of    isopropanol.

Example 10

Preparation as in example 1, but without using2,2′-azobis(isobutyronitrile) (AIBN) as initiator, and using thefollowing solution I:

-   3.0 g of epoxy resin D.E.R: 330 in solution in 100 g of isopropanol.

Example 11

Preparation as in example 1, but without using2,2′-azobis(isobutyronitrile) (AIBN) as initiator, and using thefollowing solution J:

-   4.5 g of epoxy resin D.E.R: 330 in solution in 100 g of isopropanol.

Example 12

Preparation as in example 1, but without using2,2′-azobis(isobutyronitrile) (AIBN) as initiator, and using thefollowing solution K:

-   3.0 g of dimethyldiphenylsiloxane (silanol terminated copolymer)    (No. PS084, ABCR) in solution in 100 g of isopropanol.

Example 13

Preparation as in example 3, but operating at a pH of 8.4.

Example 14

Preparation as in example 4, but operating at a pH of 8.4.

Example 15

Preparation as in example 5, but operating at a pH of 8.7.

Example 16

Preparation as in example 6, but operating at a pH of 8.4 and using asthe base, instead of NH₄OH, a solution of 2.4 g of methylamine in 20 mlof isopropanol.

Example 17

Preparation as in example 6, but operating at a pH of 8.7 and using asthe base, instead of NH₄OH, a solution of 2.4 g of methylamine in 20 mlof isopropanol.

Comparative example 18 (SiO₂ coating only)

95 g of Paliocrom L 2000 are dispersed in 310 ml of isopropanol and thedispersion is heated to the boiling point. Then 20 g oftetraethoxysilane are added and, after a short time, 13 g of H₂O.Subsequently a 25% strength aqueous NH₄OH solution is introduced via aDosimat over a period of 3 h at a rate such that, during this time, a pHof 8.7 is attained and maintained. Subsequently the reaction iscontinued for a further 3 h and then a mixture of 1 g of Dynasylan OCTEOand 0.5 g of Dynasylan AMMO is added. The reaction mixture is stirredovernight and filtered off with suction the next day. The filtercake isdried in a vacuum drying cabinet at 100° C. for 6 h.

The gassing over time is shown in table 1.

TABLE 1 Gassing tests on different Paliocrom samples Gassing in mm afterSample 7 d 14 d 21 d 28 d Example 1 1 5 11 11 Example 1 after laboratorykneader 2 3 3 3 Example 2 after laboratory kneader 3 3 4 5 Example 3after laboratory kneader 4 4 6 7 Example 4 after laboratory kneader 3 34 5 Example 5 after laboratory kneader 4 4 5 5 Example 6 afterlaboratory kneader 3 3 4 5 Example 7 after laboratory kneader 3 4 5 6Example 8 after laboratory kneader 5 5 7 8 Example 9 after laboratorykneader 6 6 7 7 Example 10 after laboratory kneader 9 9 10 11 Example 11after laboratory kneader 7 7 8 9 Example 12 after laboratory kneaderExample 13 after laboratory kneader 3 4 4 5 Example 14 after laboratorykneader 3 3 5 5 Example 15 after laboratory kneader 4 5 6 6 Example 16after laboratory kneader 3 4 4 5 Example 17 after laboratory kneader 4 46 7 Comp. example 18 0 0 0 1 Comp. example 18 after treatment in <1 d!!— — — laboratory kneader Nb: All inventive examples passed the gassingtest without treatment in the laboratory kneader.

All of the inventively coated examples passed the gassing test evenafter treatment in the laboratory kneader. The SiO₂-coated metalpigments of comparative example 18, in contrast, did not pass thegassing test for even one day following shearing treatment in thelaboratory kneader. Since the unsheared pigment passed the gassing testwith virtually no measurable evolution of gas, this shows that metalpigments provided exclusively with an inorganic coating are indeedexcellent in terms of the gassing stability, but are very unsatisfactoryin terms of the mechanical stability.

What is claimed is:
 1. Metallic effect pigments with coating, comprisinga platelet-shaped substrate, wherein the coating comprises at least onehybrid inorganic/organic layer having an average thickness of at least10 nm, the hybrid layer having at least partly an inorganic network thathas one or more inorganic oxide components, and having at least oneorganic component, the organic component being at least partly anorganic oligomer and/or polymer which is covalently bonded at leastpartly to the inorganic network via one or more organic network formers,wherein the at least partial covalent bonding of inorganic oxidecomponent and organic oligomer and/or polymer is accomplished at leastpartly through one or more organic network formers of the generalformula (I)R¹ _(n)R² _(m)R³ _(o)SiX_((4−n−m−o))  (I) where X is a hydrolyzablegroup after whose hydrolysis a covalent bond of organic network formerto the inorganic network can be formed and R¹ is a reactive organicgroup which covalently bonds to the organic oligomer and/or polymer, R²and R³ independently of one another is an organic group which iscovalently bonded to the organic oligomer and/or polymer, or R² and R³independently of one another are non-reactive, with the proviso that n,m and o are integers, with n+m+o=1 to 3 and n=1 to 3, m=0 to 2, and o=0to
 2. 2. The metallic effect pigments of claim 1, wherein the inorganicoxide component of the hybrid layer is selected from the groupconsisting of metal oxide, metal suboxide, metal hydroxide, metal oxidehydrate, and mixtures thereof.
 3. The metallic effect pigments of claim2, wherein the inorganic oxide component of the hybrid layer is selectedfrom metal oxide and/or metal suboxide and/or metal hydroxide and/ormetal oxide hydrate of elements from the group consisting of silicon,aluminum, titanium, zirconium, iron, cerium, chromium, manganese, zinc,tin, antimony, boron, magnesium, and mixtures thereof.
 4. The metalliceffect pigments of claim 1, wherein the organic network former is asilane of the general formula (I), the hydrolyzable group(s) X beingselected independently of one another from the group consisting ofhalogen, hydroxyl, alkoxy having 1-10 C atoms, which may bestraight-chain or branched, and mixtures thereof.
 5. The metallic effectpigments of claim 1, wherein R¹ is a reactive organic radical which hasone or more substituents selected from the group consisting of amino,hydroxyl, thiol, epoxy, acrylate, methacrylate, vinyl, allyl, alkenyl,alkynyl, carboxyl, carboxylic anhydride, isocyanate, cyanate, ureido,and carbamate group and mixtures thereof.
 6. The metallic effectpigments of claim 1, wherein R² and R³ are selected independently of oneanother from the group consisting of H—, (C₁-C₄₀)-alkyl-,(C₁-C₄₀)-fluorinated alkyl-, (C₁-C₄₀)-partially fluorinated alkyl-;(C₂-C₄₀)-alkenyl-, (C₂-C₄₀)-alkynyl-; (C₆-C₃₆)-aryl-, fluorinated(C₆-C₃₆)-aryl-, partially fluorinated (C₆-C₃₆)-aryl-;(C₇-C₄₀)-alkylaryl-, (C₇-C₄₀)-arylalkyl-, fluorinated(C₇-C₄₀)-alkylaryl-, partially fluorinated (C₇-C₄₀)-alkylaryl-;(C₈-C₄₀)-alkenylaryl-, (C₈-C₄₀)-arylalkynyl-, -; (C₈-C₄₀)-alkynylaryl-;(C₅-C₄₀)-cycloalkyl-, (C₆-C₄₀)-alkylcycloalkyl-,(C₆-C₄₀)-cycloalkylalkylsilanes each of which may be substituted byamino, hydroxyl, thiol, epoxy, acrylate, methacrylate, vinyl, allyl,alkenyl, alkynyl, carboxyl, carboxylic anhydride, isocyanate, cyanate,ureido, carbamate and/or ester group and may contain 0, N, and S asheteroatoms in the carbon chains and carbon ring systems, and mixturesthereof.
 7. The metallic effect pigments of claim 1, wherein theoligomer and/or polymer is constructed from organic monomers providedwith functionalities from the group consisting of amino, hydroxyl,thiol, epoxy, acrylate, methacrylate, vinyl, allyl, alkenyl, alkynyl,carboxyl, carboxylic anhydride, isocyanate, cyanate, ureido, andcarbamate group and mixtures thereof.
 8. The metallic effect pigments ofclaim 1, wherein the organic component is constructed from reactiveorganic oligomers and/or polymers which have reactive groups which areable to attach to the inorganic network and/or at least to the group R¹of the organic network formers.
 9. The metallic effect pigments of claim8, wherein the reactive organic oligomer and/or polymer is selected fromthe group consisting of silanol- and/or methoxy-terminated silicones,trialkoxysilane-modified polyethyleneimines,polyarylalkylsilasesquioxanes, aminosilane-modified polyethylene oxideurethanes, and mixtures thereof.
 10. The metallic effect pigments ofclaim 8, wherein the reactive organic oligomer and/or polymer isselected from the group consisting of polyacrylates, polymethacrylates,polyethers, polyesters, polyamines, polyamides, polyols, polyurethanes,and polyolefins, these oligomers and/or polymers having reactivefunctional groups which are able to bond to the inorganic network or anorganic network former.
 11. The metallic effect pigments of claim 1,wherein the organic oligomer and/or polymer is covalently bonded via thefunctional groups R¹ of one or more organic network formers in thehybrid inorganic/organic layer.
 12. The metallic effect pigments ofclaim 1, wherein the hybrid inorganic/organic layer is additionallymodified by one or more organic network modifiers having the generalformula (III)R¹ _(n)R² _(m)R³ _(o)SiX_((4−n−m−o))  (III) where X is a hydrolyzablegroup after whose hydrolysis a covalent bond of organic network modifierto the inorganic network can be formed, and R¹, R², and R³ independentlyof one another are each a nonreactive organic group, with the provisothat n, m and o are integers, where n+m+o=1 to 3 and n=1 to 3, m=0 to 2,and o =0 to 2, and/or by one or more organic network modifiers havingthe general formula (IV)R⁴ _(p)MX_((k−p))  (IV) where the compound has at least one hydrolysablegroup X after whose hydrolysis a covalent bond of organic networkmodifier to the inorganic network can be formed, and has at least onenonreactive organic radical R⁴, where k is the formal oxidation numberof M, M is Al, Zr or Ti, and p is an integer from 1 to (k−1).
 13. Themetallic effect pigments of claim 1, wherein the platelet-shapedsubstrate is composed of metals or metal compounds selected from thegroup consisting of aluminum, copper, iron, zinc, tin, titanium,chromium, cobalt, silver, nickel, antimony, magnesium, zirconium,silicon, and mixtures and alloys thereof.
 14. The metallic effectpigments of claim 13, wherein the platelet-shaped substrates consistessentially of iron and wherein said substrates are produced fromreduced carbonyliron.
 15. The metallic effect pigments of claim 1,wherein disposed between the substrate and the hybrid inorganic/organiclayer is at least one separate layer consisting essentially of aninorganic material and/or at least one separate layer consistingessentially of an organic polymer.
 16. The metallic effect pigments ofclaim 1, wherein disposed on the hybrid inorganic/organic layer there isat least one separate layer consisting essentially of an inorganicmaterial and/or at least one separate layer consisting essentially of anorganic polymer.
 17. The metallic effect pigments of claim 15, whereinat least one separate layer consisting essentially of an inorganicmaterial is composed of metal oxide and/or metal oxide hydrate and/ormetal suboxide and/or metal hydroxide and/or metal peroxide of elementsselected from the group consisting of silicon, titanium, aluminum,zirconium, iron, copper, tin, cobalt, chromium, cerium, zinc, antimony,manganese, nickel, yttrium, molybdenum, vanadium, tantalum, tungsten,and mixtures thereof.
 18. The metallic effect pigments of claim 15,wherein at least one separate layer consisting essentially of an organicpolymer is selected from the group consisting of polyacrylate,polymethacrylate, polyether, polyester, polyamine, polyamide, polyol,polyurethane, polyphenolformaldehyde, polyolefin,poly-1,2,3,4-tetrafluoroethylene, and mixtures thereof.
 19. The metalliceffect pigments of claim 1, wherein an additional layer with one or moresurface modifiers has been applied to the surface of the coated metalliceffect pigments.
 20. The metallic effect pigments of claim 1, wherein anorganic fraction in the hybrid inorganic/organic layer is in a range offrom 4% to 85% by weight, based on the weight of the entire hybridlayer.
 21. The metallic effect pigments of claim 1, wherein the organicoligomers of the hybrid layer have a linking of two to twenty monomerunits.
 22. The metallic effect pigments of claim 1, wherein the organicpolymers of the hybrid layer have a linking of more than twenty monomerunits.
 23. The metallic effect pigments of claim 1, wherein the hybridlayer is formed with mutual interpenetration of the inorganic networkand the organic oligomers and/or polymers.
 24. The metallic effectpigments of claim 13, wherein the platelet-shaped substrate is composedof metals or metal compounds selected from the group consisting of goldbronzes, brass, stainless steel and steel.